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LE AFLET

Buchholz relayGas accumulation and oil flow monitoring

A buchholz relay is a fundamental

device for transformers, it keeps internal gas accumulation and oil flow monitored and under control.

Transformer outages have a considerable economic Another important functionality of the Buchholz impact on the operation of a power supply network. relay is to operate if oil flow from the transformer Therefore it is the aim to ensure an accurate tank to the oil conservator. In case the oil flow speed assessment of the transformer condition. exceed the pre-set value the flow vent operates and switch the trip contact. Partial discharges, leakage currents, hot spots and arcing are phenomena that contribute to Application: degradation of oil insulationg performances by • Liquid-filled transformers with generating dangerous gas flow inside the or without rubber bag transformer tank. • Transformer conservator • Transformer tank ABB COMEM has developed a reliable Buchholz relay that promptly provide information about internal Features: malfunctioning giving the possibility to eventually • Field-proven reliability stop the system prior its destruction. • No false alarms • Robust design The Buchholz relay is sited in the pipework between • IP 65, upon request IP 66 the transformer and its conservator and it is filled • Special design for On-load tap-changer (OLTC) with oil during normal transformer operation. application, hermetic transformers and transformers with conservator with rubber bag When gas is generated in the transformer it rises towards the conservator and collects in the upper Additional accessories: chamber of the relay. The oil level drops and the top • Gas sampling device float triggers alarm switch. Gas shall not freely pass from the relay body and escape into the pipework before the alarm contact has operated. TECHNICAL DATA Housing Alluminum alloy

Inspection glass Tempered glass with UV filter

Oil temperature from -40°C up to +120°C

from -40°C up to +80°C Environment temperature Lower temperature version available upon request Indoors and outdoors, tropical proof Installation Off shore protection available upon request Switches Up to 4

Max. nominal current 2A

Min. switching current 10mA/24 VDC (for lower current the golden contact is available)